How IAGG’s Research Exposes the Dangers of Multiple Medications in Older Adult Patients

The world’s population is aging at an unprecedented pace. By the middle of this century, adults aged 65 and older will outnumber children in many regions, and the majority of those older adults will be managing two or more chronic health conditions simultaneously. More conditions typically mean more medications — and more medications, particularly in aging bodies, carry risks that clinicians, policymakers, and patients themselves are still learning to fully appreciate.

The International Association of Gerontology and Geriatrics (IAGG) has long positioned itself as a global leader in research and advocacy focused on older adult health. Among the most urgent issues the organization has highlighted is the growing problem of polypharmacy — the concurrent use of multiple medications — and the profound, often underestimated dangers it poses to elderly patients. Through peer-reviewed research, international congresses, and collaborative clinical guidelines, IAGG has helped bring this issue from the margins of geriatric medicine to the center of patient safety discussions worldwide.

Understanding Polypharmacy: Where Clinical Necessity Meets Clinical Risk

In geriatric medicine, polypharmacy is most commonly defined as the regular use of five or more medications by a single patient. A more severe category — hyperpolypharmacy — applies when a patient is taking ten or more drugs concurrently. These definitions matter because research consistently shows that risk escalates sharply as the number of medications increases, and not in a simple, linear fashion.

What makes polypharmacy such a difficult clinical challenge is that it is rarely the product of careless medicine. In most cases, each medication in a patient’s regimen was prescribed for a legitimate reason by a qualified clinician. The problem is systemic: healthcare systems that manage chronic conditions in siloes, patients who see multiple specialists who may not communicate with one another, and prescribing norms developed largely for younger adults all contribute to medication accumulation over time.

IAGG research emphasizes that polypharmacy should be approached as a clinical condition in its own right — one that demands the same vigilance, monitoring, and management as the diseases the medications are meant to treat. Recognizing it as such is the first step toward preventing the harms it causes.

Why the Aging Body Processes Drugs Differently

A central insight running through the body of research that IAGG has championed is this: older adults are not simply older versions of younger patients. The physiological changes that accompany aging fundamentally alter the way medications are absorbed, distributed, metabolized, and eliminated from the body. Standard prescribing guidelines are often derived from clinical trials conducted predominantly in younger, healthier populations — a gap that leaves elderly patients particularly exposed to medication-related harm.

The International Association of Gerontology and Geriatrics has consistently highlighted the need for prescribers to account for these age-related pharmacokinetic and pharmacodynamic changes. The table below outlines the key physiological shifts that make older adults more vulnerable to the effects of multiple medications.

When these changes occur in a patient already carrying a heavy medication burden, the interactions between drugs and a less-efficient physiology multiply. A dose that is therapeutic in a 45-year-old may become toxic in a 78-year-old with declining kidney and liver function — and that toxicity may not be immediately recognized as medication-related.

The Documented Dangers: What Polypharmacy Does to Older Adults

IAGG research has helped document a broad and serious range of health consequences associated with polypharmacy in elderly patients. These harms are rarely sudden or obvious. They tend to develop insidiously, often masquerading as age-related deterioration rather than the medication-driven events they actually are.

Adverse Drug Reactions and the Danger of Drug–Drug Interactions

Adverse drug reactions (ADRs) represent one of the most well-established and serious consequences of polypharmacy. What makes the risk particularly alarming is that it does not grow proportionally with the number of medications taken — it escalates exponentially. Research in geriatric pharmacology, a field IAGG has actively supported and promoted, demonstrates that patients on five medications face dramatically higher ADR risk than those on two, and patients on ten or more face a risk that is substantially greater still.

A major driver of ADRs is drug–drug interactions — situations where two or more medications interfere with one another’s metabolism, amplify each other’s effects, or compete for the same biological pathways. The following combinations are among those most frequently implicated in serious adverse events in older adult patients:

• Anticoagulants such as warfarin combined with NSAIDs or aspirin, significantly increasing the risk of dangerous internal bleeding
• ACE inhibitors used alongside potassium-sparing diuretics, which can drive serum potassium to hazardous levels
• Multiple medications with anticholinergic properties, whose sedating and cognitively impairing effects accumulate across drug classes
• Sedative-hypnotics combined with opioid analgesics, compounding the risk of respiratory suppression
• Several antihypertensive agents taken together without coordinated titration, causing unpredictable and potentially dangerous drops in blood pressure

These are not rare or theoretical scenarios. They represent everyday realities in geriatric care, and IAGG highlights that identifying and managing them requires systems, education, and clinical tools that many healthcare environments have yet to fully implement.

Falls, Fractures, and the Physical Toll of Medication Burden

Falls are among the most devastating consequences of aging and represent a leading cause of injury-related mortality and disability in older adults globally. IAGG research draws a clear and significant connection between polypharmacy and fall risk. Medications that affect blood pressure, balance, reaction time, alertness, or muscle coordination — including antihypertensives, benzodiazepines, antidepressants, antipsychotics, and opioids — are each independently associated with increased fall frequency.

When several such medications are used simultaneously, their effects on stability and neuromuscular coordination compound one another. An older patient taking three or four drugs that each individually increase fall risk may face a cumulative risk that is far greater than any single drug would produce on its own. The downstream consequences — hip fractures, traumatic brain injuries, prolonged hospitalizations, and loss of independent living — illustrate why IAGG considers medication-related falls a critical patient safety priority.

Cognitive Impairment and the Prescribing Cascade

Perhaps the most underappreciated danger of polypharmacy is its contribution to cognitive decline in older adults. Several commonly prescribed drug classes — including anticholinergics, benzodiazepines, opioids, and some antihistamines — are associated with reduced cognitive performance, confusion, and, in acute settings, delirium. When multiple such agents are combined, the cognitive burden can be substantial.

IAGG research has placed particular emphasis on a phenomenon that directly links polypharmacy to its own perpetuation: the prescribing cascade. This occurs when a side effect of one medication is misidentified as a new, separate medical condition and treated with an additional prescription. That second drug may itself produce side effects that prompt a third prescription — and so on. A patient who develops constipation from an opioid, receives a laxative, then develops diarrhea and is prescribed an anti-diarrheal agent, is experiencing a prescribing cascade in its simplest form. In more complex cases, the cascade can result in patients taking a half-dozen medications, several of which exist solely to manage the effects of other drugs they never needed in the first place.

High-Risk Medication Classes Identified in Geriatric Research

Not all medications carry equal risk in older adult patients. Research reviewed and disseminated by the International Association of Gerontology and Geriatrics has helped identify specific drug classes that warrant particular caution when prescribed to elderly individuals. These medications are not necessarily inappropriate for all older adults — but they require greater vigilance, lower starting doses, more frequent monitoring, and clearer justification than they might in younger patients.

The following medication categories appear most consistently in geriatric prescribing research as carrying elevated risk in older adult populations:

1. Anticholinergic medications — including certain bladder relaxants, older antidepressants, and first-generation antihistamines — are associated with memory impairment, confusion, dry mouth, constipation, urinary retention, and falls. Cumulative anticholinergic burden across multiple drugs is a growing clinical concern.
2. Benzodiazepines and non-benzodiazepine sedative-hypnotics — widely prescribed for anxiety and insomnia — carry a well-documented risk of falls, hip fractures, respiratory depression, cognitive impairment, and physiological dependence.
3. Non-steroidal anti-inflammatory drugs (NSAIDs) — linked to gastrointestinal bleeding, acute kidney injury, and cardiovascular events, all of which are more serious in older adults with reduced physiological reserves.
4. Sulfonylureas and insulin — effective treatments for diabetes, but capable of causing severe hypoglycemia in older patients with irregular eating, reduced kidney function, or altered drug metabolism.
5. Antipsychotic medications — associated with increased stroke risk, metabolic complications, excessive sedation, and falls, particularly when used off-label in older adults with dementia.
6. Anticoagulants — essential for stroke prevention and clot management, but requiring careful monitoring in frail older patients who are already at elevated bleeding and fall risk.
7. Digoxin — a narrow-therapeutic-index drug that is renally excreted; accumulation in the context of declining kidney function can lead to life-threatening toxicity even at doses that appear standard.

Understanding these high-risk categories is foundational to the safer prescribing culture that IAGG advocates for in health systems around the world. The goal is not to withhold necessary treatment, but to ensure that every drug prescribed has a defensible current indication and that its risks are actively weighed against its benefits for each individual patient.

IAGG’s Advocacy for Deprescribing and Structured Medication Review

Among the most significant contributions of International Association of Gerontology and Geriatrics to contemporary geriatric medicine is its sustained support for deprescribing — the supervised, intentional process of reducing or discontinuing medications whose risks outweigh their benefits for a given patient at a given time. The concept challenges a long-standing prescribing culture in which adding medications is routine, but removing them is viewed with suspicion or simply overlooked.

IAGG research suggests that structured medication reviews, conducted regularly and involving the full clinical team, can meaningfully reduce ADR rates, hospitalizations, and polypharmacy-related harm without compromising patient outcomes. For this to happen, deprescribing must be approached systematically and collaboratively, not as an ad hoc decision made by a single clinician with incomplete information about a patient’s full medication regimen.

The principles that IAGG research and policy positions consistently support in addressing polypharmacy include the following:

• Routine, structured medication reviews for all patients aged 65 and older who are taking five or more medications, conducted at least annually and at every major care transition
• Adoption of validated clinical screening tools — such as the STOPP (Screening Tool of Older People’s Prescriptions) and START (Screening Tool to Alert to Right Treatment) criteria — to systematically identify potentially inappropriate prescribing and critical prescribing omissions
• Active involvement of patients and their caregivers in discussions about medication goals, risks, and preferences — treating deprescribing as a shared decision rather than a unilateral clinical choice
• Reassessment of medication appropriateness in the context of changing goals of care, particularly in patients with advanced frailty, serious illness, or limited life expectancy
• Improved cross-provider communication and medication reconciliation at all care transitions — discharge from hospital, transfer between facilities, initiation of home care — to catch duplications, interactions, and inappropriate carryovers
• Systemic education for all members of the care team on recognizing and responding to signs of medication-related harm before adverse events occur

These are not simply best practices for individual clinicians. They represent a framework for transforming how healthcare systems approach older adult care — a transformation that IAGG has been promoting on the international stage for decades.

The Role of Multidisciplinary Teams in Combating Medication Harm

IAGG has consistently argued that no single profession can bear sole responsibility for managing polypharmacy in older adults. The complexity of multi-drug regimens in patients with multiple comorbidities demands a team-based approach that draws on the expertise of geriatricians, primary care physicians, clinical pharmacists, nurses, and allied health professionals working in genuine coordination.

Clinical pharmacists occupy a particularly important — and often underleveraged — role in this effort. Where pharmacist-led medication review services have been integrated into geriatric care, the evidence shows meaningful reductions in medication errors, inappropriate prescribing, and preventable ADRs. IAGG has advocated internationally for expanding the clinical pharmacist’s role in elder care settings, recognizing that medication safety in complex patients is too consequential to rest on a single professional’s shoulders.

Nursing staff, who maintain the most continuous contact with hospitalized and long-term care patients, are also essential to medication safety in older adults. They are frequently the first to observe early warning signs of an adverse drug reaction — changes in cognition, unexplained fatigue, altered appetite, new instability. Equipping nursing teams with the knowledge to recognize and escalate these signals, consistent with evidence-based frameworks that IAGG promotes, is a practical and high-impact strategy for preventing medication-related harm.

A Global Problem Demanding Global Solutions

The implications of polypharmacy extend well beyond individual patient encounters. At the health system level, medication-related harm in older adults constitutes an enormous — and substantially preventable — burden on hospitals, emergency departments, rehabilitation services, and long-term care facilities. Adverse drug events are consistently among the most frequent causes of unplanned hospital admissions in older adults, and research reviewed by IAGG confirms that a significant proportion of those admissions are avoidable.

As the global population continues to age, the economic, social, and human costs of unmanaged polypharmacy will grow unless systemic change occurs. IAGG’s research contributes indispensable evidence to guide that change — from national medication safety standards and pharmacovigilance programs to reimbursement models that reward comprehensive medication review rather than perpetuating the prescribe-first, assess-later culture that has long dominated much of healthcare.

Conclusion

Polypharmacy in older adults is not an unsolvable problem. It is a complex, multidimensional challenge that responds to evidence-based intervention, interdisciplinary collaboration, and genuine commitment to patient-centered care. The body of research advanced and promoted by the International Association of Gerontology and Geriatrics has provided much of the scientific foundation needed to address it effectively.

IAGG has established clearly that the dangers of multiple medications in older adult patients — adverse drug reactions, drug–drug interactions, falls, cognitive impairment, and the self-perpetuating prescribing cascade — are neither inevitable nor untreatable. They are, in large measure, consequences of prescribing systems that have historically underestimated the vulnerability of aging physiology and the compounding risks of medication accumulation.

By advancing rigorous research, promoting evidence-based tools for medication review and deprescribing, and advocating for the kind of multidisciplinary team-based care that older adults deserve, IAGG continues to translate scientific knowledge into practical protection. The research exists. The tools are available. What remains is the collective will to apply them consistently — and in doing so, to make the care of older adults meaningfully safer.